Paleofantasy: What Evolution Really Tells Us about Sex, Diet, and How We Live (14 page)

The analysis of our internal microbiome, the diverse array of microscopic organisms living on and inside of us, is one of the most exciting emerging sciences. It may help us understand how the Somali, the Hadza, and the Finns evolved convergent digestive abilities, despite their wide geographic separation. Consumption of dairy exquisitely illustrates the ongoing nature of evolution, in humans as in other living things. Our ancestors had different diets, and almost certainly different gut flora, than we have. We continue to evolve with our internal menagerie of microorganisms just as we did with our cattle, and they with us.

5

The Perfect Paleofantasy Diet

MEAT, GRAINS, AND COOKING

I
n late 2010, headlines and blogs were full of a new discovery about Paleolithic humans. Every major news outlet and many of the more obscure ones covered the finding, with the usual interviews of the study’s authors, comments by experts not involved in the research, and speculations about its implications for modern urban life.

The discovery was not a new fossil, or a redrawing of the map of human migration out of Africa. It was not an analysis of ancient DNA, or even of the human form at all. Anna Revedin of the Italian Institute of Prehistory and Early History in Florence, along with her Italian and Czech colleagues, detected bits of starch grains from plants, including cattail-like root particles, on the grinding stones from 30,000-year-old archaeological sites in Italy, Russia, and the Czech Republic. The scientists concluded that our ancestors were making flour and mixing the ground-up plants with water to make what one member of the team, Laura Longo, called “a kind of pita,” cooked on a stone heated in the fire.
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Several related recent discoveries went more directly to the way hominins not only prepared but consumed starch: the teeth. A team of researchers led by anthropologist Amanda Henry analyzed the plaque clinging to teeth of Neandertals, which seem to have survived, in those preflossing days, with the remnants of meals intact.
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The plaque is easily distinguished from dirt or other contaminants on the teeth, and Henry and her colleagues found clear evidence of grass seeds, date palms, and a few other plants. What’s more, the outer parts of the starch grains were gelatinized—a transformation that occurs only via heating, which means that Neandertals cooked their food. Interestingly, the various plants found in the ancient teeth are ripe at different times of year, suggesting further that the Neandertals may have returned to various sites to harvest the grains. Another study by Henry and colleagues found similar plant remains in the 2-million-year-old teeth of
Australopithecus sediba
from South Africa.
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The two individuals examined also had remains of bark and wood in their teeth, as well as a wide variety of leaves and other softer plant material. This diet bears a strong resemblance to that of most living primates, but not to the supposedly carnivorous human ancestors cited by the paleo enthusiasts.

So early humans ate crackers. What’s the big deal? Modern versions of cattails and the other plants found in the remains associated with the grinding tools, such as bur reed, are known to be nutritious; archaeology blogger Kris Hirst noted that a single hectare of cattails produces 8 tons of flour.
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The ground roots could be stored and transported, making people less dependent on the seasonal availability of game animals. Why wouldn’t we expect our ancestors to have taken advantage of this useful resource?

The answer is that a reliance on starch in the diet calls into question the various forms of the so-called paleo diet, which, as I mentioned earlier, uses our ancestors as models for the way we should be eating. If people are vociferous in their opinions about milk, they are positively fervent in their feelings about grains and other carbohydrates as suitable components of the diet. “Bread” and “pasta” seem to be fighting words for many of the proponents of a diet more like that of early humans. From the
New York Times
Well
blog, for example, comes this quote: “Cereal grains like wheat, oats, barley, rye, maize and rice we started to consume between only 5,000 and 10,000 years ago and we are not used to it. Genetically we are still the hunter-gatherers from 190,000 years ago, adapted to meats, fruits and vegetables.”
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Eschewing grains often seems to be accompanied by an enthusiasm for carnivory, as this comment from Cavemanforum.com illustrates: “I personally can never get enough of pork belly (bacon without the crap). Yesterday, I had it with breakfast, lunch and dinner! At dinnertime, I had a pound of salmon steak, but I decided to fry up some pork belly afterwards. It’s a good feeling.”
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The first formalized suggestion that we should be relying on meat and modeling ourselves, at least foodwise, after our cave-dwelling ancestors came from
The Stone Age Diet
, a 1975 book by gastroenterologist Walter Voegtlin. Like its more recent successors, including
The Paleo Diet
,
⁷
We Want to Live
,
⁸
and
The Paleo Solution: The Original Human Diet
,
⁹
The Stone Age Diet
bemoans the modern Western diet of processed food high in starches. Voegtlin disapprovingly describes the average North American dinner of the time, in which “The average meat serving is modest and is often replaced with baked beans, macaroni and cheese, soy bean meat substitutes, or peanut butter. An array of vegetables is dwarfed by a mountain of mashed potatoes and gravy or a giant baked potato. Most families have bread or rolls with butter at dinner. Dessert is about the same as lunch [pie, cake, pudding, ice cream], only more of it.”
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This way of eating, according to the supporters of various forms of the paleo diet, is responsible for our current obesity crisis, as well as the various “diseases of civilization,” including type 2 diabetes, hypertension, and atherosclerosis. The problem, they claim, is that humans have not adapted to be able to safely consume grains, agriculture having arisen a mere 10,000 years ago, and hence reliance on carbohydrates takes us on an unhealthy and dangerously untrodden path from the diet we evolved to eat, which is meat based. The diets differ in their details, with various amounts and types of vegetables permitted, but they share an emphasis on meat and strictures against virtually all sweets and products using flour. A sample breakfast might include fruit and pork chops with herbal tea; snacks might consist of dried fish or meat and walnuts.

Voegtlin is dismissive of vegetarians, advocating a virtually completely carnivorous diet based on his (inaccurate, as I will explain) view of our evolutionary history. He declaims, “Did anybody ever tell you that your ancestors were exclusively flesh-eaters for at least two and possibly twenty
million
years? Were you aware that ancestral man first departed slightly from a strictly carnivorous diet a mere ten
thousand
years ago?”
¹¹

Voegtlin also warns against misapplying the evolutionary principles he promotes, with a story that one only hopes is apocryphal:

The puerile syllogism that 1) man descended from apes; 2) apes eat coconuts; therefore 3) man should eat coconuts, impelled German August Engelhart [
sic
] to gather about him a group of disciples dedicated to eating nothing but coconuts. The community migrated to and became established on a South Pacific atoll. A fanatical disciplinarian, Engelhart decreed imprisonment and torture for those deviating in the slightest from the coconut diet. When the atoll was captured by the British during World War I only one survivor of the company was found—Engelhart himself—his legs swollen from starvation and his body a mass of putrid ulcers. He died shortly after being taken from the atoll with its abundant fish and shellfish population, which could have saved all the “cocovores” from protein malnutrition and death.
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Needless to say, current versions of the paleo diet do not assume that vegetarians are sticking to one food, coconuts or not. The fans of paleo also acknowledge that they are not necessarily emulating ancestral diets in every respect, but using them as a jumping-off point. They still, however, eschew plant-based diets. The paleo lifestyle has been embraced by many people, with a number of informal online discussion groups arising in which practitioners share advice and ask questions. Cookbooks with titles like
Paleo Comfort Foods: Homestyle Cooking in a Gluten-Free Kitchen
and
The Paleo Diet for Athletes: A Nutritional Formula for Peak Athletic Performance
cater to specialized applications of the paleo diet.

The level of dietary and other detail is astonishing. Depending on where you look, people are advised to use coconut oil instead of olive oil, olive oil instead of coconut oil, or butter instead of either; to restrict nuts, or to eat macadamias instead of almonds; not to worry about eating nearly 6 pounds of ground beef in a day, but to be concerned about the high sugar content of watermelon; and to go to sleep when it is dark and wake when it is light, avoiding the use of alarm clocks. (Application of the latter recommendation to those people living in Scandinavia in the summertime is not addressed.) One practitioner consulted with a paleo discussion board because of a concern that eating more carbs was making his/her nose rounder (“when i stick to meat fat and veggies, it is pointier . . .”
¹³
). Others extend the back-to-the-cave movement to clothing, wondering which type of natural fibers—wool, silk, linen, or cotton—might be the most appropriate to wear (synthetics, of course, are out), calling to mind an interesting image of cave-based silkworm farms. Also, I can’t be completely sure, but apparently some followers are eating horse fat. Is this really the solution to our health problems?

Amber fields of . . . game?

At a recent conference I attended,
¹⁴
Loren Cordain, author of
The Paleo Diet
and a well-known proponent of eating fewer refined grains as the key to health, gave a presentation to a small group of scientists interested in evolution and medicine. He outlined in persuasive detail the digestive and other health consequences of eating certain foods for people who have an alteration in a particular immune system gene. Potential offenders ranged from green tomatoes and root beer (not too much of a problem to give up) to bread, rice, and potatoes (ouch). Many of us can eat these foods with impunity, but to those unlucky enough to bear the gene variant, the foods can eventually cause something called “leaky gut,” which you don’t have to know anything about to know is something you don’t want.

I was greatly intrigued by this information (and am cautiously optimistic that my gut is impervious, at least for the time being), but one thing puzzled me. Why, I asked Cordain, has this inability to properly digest all these common foods persisted? Surely it should have been selected out of the population.

He was taken aback. The answer was obvious, he responded. The sensitivity had been occurring only since the advent of agriculture, so humans haven’t had an opportunity to adapt yet. I frowned. “Plenty of time,” I said.

“But it’s only been ten thousand years,” he said.

“Plenty of time,” I repeated. Now it was his turn to frown. We never resolved our disagreement, but it points to a question that is at the crux of this book. Is the diet envisioned by Cordain and other paleo proponents really “the one and only diet that ideally fits our genetic makeup,”
¹⁵
as his book would have it? Is it true, as he claims, that “just 500 generations ago—and for 2.5 million years before that—every human on Earth ate this way”?
¹⁶
We know that the lactase gene, for example, evolved quickly, allowing humans who could not have consumed dairy products without discomfort to do so if they inherited the gene. What about the rest of our digestion-related genes?

I want to make it clear that I am not discussing the relative health merits of the paleo versus Atkins versus Mediterranean diets, or any other particular way of eating. I am also not concerned with the details of exactly how much animal protein in the diet is necessary to constitute a real paleo diet, or which micronutrients would have been present in which quantities of food in the period before agriculture. I also realize that not all paleo dieters are doing exactly the same thing, and that not all are really attempting to replicate ancient meals.

What’s more, although I confess to a certain bemused fascination with the minutiae of, for example, how large a yam one can consume and still have the overall diet be considered paleo, I realize that virtually all diets—vegan, vegetarian, organic, and so on—have their fringe adherents, some of whom can become quite vehement. Many paleo eaters complain about being chided by virtuous vegetarians; one commenter on a blog who has not “knowingly consumed grain products for about 10 years, as well as processed sugary things” is “often lectured by people how humans can’t survive without grains and must eat them (usually they are slightly overweight, puffy people who complain of various ailments).”
¹⁷
And certainly, eating mainly lean meat and few or no processed foods may well be healthy for at least some people, particularly when contrasted to a diet of Cheetos and Coca-Cola. The question is whether the various forms of the paleo diet really do replicate what our ancestors ate, and further, whether that should serve as a guide for us in the twenty-first century.

Nevertheless, the studies of the quality of paleo diets are at best mixed in their evaluations. In 2011,
U.S. News & World Report
had twenty-two experts, including physicians and professors of food science and nutrition at universities and medical schools, rank a variety of popular and relatively unknown diet plans, including various low-fat and low-carb options, as well as the paleo diet.
¹⁸
Then the experts “rated each diet in seven categories: how easy it is to follow [1], its ability to produce short-term [2] and long-term [3] weight loss, its nutritional completeness [4], its safety [5], and its potential for preventing and managing diabetes [6] and heart disease [7]. We also asked the panelists to let us know about aspects of each diet they particularly liked or disliked and to weigh in with tidbits of advice that someone considering a particular diet should know.”
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The magazine defined the paleo diet as “the way we ate when we were hunting and gathering: animal protein and plants . . . if the cavemen didn’t eat it, you shouldn’t either. So long to refined sugar, dairy, legumes, and grains (this is pre-agricultural revolution); hello to meat, fish, poultry, fruits, and veggies.”
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